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Intensity of the incident light

  • Thread starter vrobins1
  • Start date
22
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1. Homework Statement

Unpolarized light is incident on a system of three polarizers. The second polarizer is oriented at an angle of 33.0° with respect to the first and the third is oriented at an angle of 45.0° with respect to the first. If the light that emerges from the system has an intensity of 2.3 W/m2, what is the intensity of the incident light?

2. Homework Equations

Iout=Iincos2[tex]\theta[/tex]

3. The Attempt at a Solution

I know that after I0 passes through the first polarizer, it is 1/2I0. After it passes through the second, I thought it would be 1/2I0cos2(33), and after it passes through the third, 1/2I0cos2(33)cos2(45).
This would all equal 2.3, which I was given.
So I set up my final equation as:
1/2I0cos2(33)cos2(45) = 2.3, or
I0= 2.3 / (1/2cos2(33)cos2(45).

I solved and got 13.08, but that is incorrect. Can anyone offer any insight? Thanks.
 

Answers and Replies

Redbelly98
Staff Emeritus
Science Advisor
Homework Helper
12,038
128
For the third polarizer, use the angle between it and the second polarizer.

45° is the angle between the third and first polarizer.
 

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